Downhole tool and uses thereof

ABSTRACT

There is provided a downhole tool that can be used to grind down and remove scale and debris that has built up within a wellbore. The downhole tool has a drill bit that has an outer surface for engaging a wellbore and defines a bit bore. The drill bit has a first end defining a bit face and a second end adapted to engage a drive pipe. The drill bit also has a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from a wellbore. In some cases, the projection comprises a plurality of projections. Generally, the scale and debris are at least partially removed from the wellbore when ground down by the downhole tool comprising the projection.

FIELD

The present disclosure relates generally to well equipment for bore holes. More particularly, the present disclosure relates to a downhole tool and uses thereof.

BACKGROUND

Wellbores in, for example, the oil and gas industry can build up scale and other debris. Scale can be caused by a deposition of, for example, various salts, oxides, silicates, and/or phosphates onto surfaces within a well, such as an oil well, a gas well, a water well, etc. Some specific, non-limiting examples of scale include metal salts and oxides, such as calcium carbonate, calcium sulfate, barium sulfate, strontium sulfate, iron sulfide, iron oxides, etc. When wellbores accumulate a considerable build-up of hard scale and debris they can become subject to clogging and the scale and debris must be removed, for example by a well service rig. On occasion, well bore debris may also result from mechanical sources within the well bore. There remains a need for equipment that facilitates removal of a build-up of scale and debris from all sources within wellbores.

SUMMARY

Herein described is a downhole tool that can be used to grind down and remove scale and debris that has built up within a defined wellbore, including but not limited to cased wellbores, uncased wellbores, and combinations thereof including but not limited to wellbores with barefoot completions. The downhole tool comprises a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore therethrough, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe; and a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from a wellbore. In some embodiments, the projection comprises a plurality of projections.

Generally, the projection separates or detaches the scale and debris from the wellbore, at least partially breaks up, grinds down or crushes the scale and debris, and the scale and debris are at least partially removed from the wellbore by circulation of fluids, reverse circulation of fluids, or a combination thereof. In an embodiment disclosed, the scale and debris is substantially separated or detached from the wellbore. In an embodiment disclosed, the scale and debris is substantially removed from the wellbore by circulation of fluids, reverse circulation of fluids or a combination thereof, i.e. sequentially.

In a first aspect, the present disclosure provides a downhole tool, including a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe, and a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from the wellbore.

In an embodiment disclosed the projection comprises a plurality of projections.

In an embodiment disclosed each of the plurality of projections is circumferentially displaced relative to each other.

In an embodiment disclosed each of the plurality of projections is longitudinally displaced relative to each other.

In an embodiment disclosed each of the plurality of projections are circumferentially and longitudinally displaced relative to each other and spiral along the outer surface of the drill bit. The plurality of projections may be oriented in a general “spiral” orientation.

In an embodiment disclosed the outer surface of the drill bit has a substantially frustoconical-shaped section proximal the first end, and a substantially cylinder shaped section.

In an embodiment disclosed the outer surface of the drill bit has a substantially cylinder-shaped section abutting the second end, and a substantially frustoconical-shaped section abutting the substantially cylinder-shaped section and terminating at the first end.

In an embodiment disclosed the projection extends substantially perpendicular from the outer surface of the drill bit.

In an embodiment disclosed the projection extends from the outer surface between about 1 mm and about 10 mm.

In an embodiment disclosed at least one of the plurality of projections extends beyond an outer diameter of the cylinder-shaped section, by an undercut height.

In an embodiment disclosed the undercut height is a maximum of 10 mm.

In an embodiment disclosed the undercut height is between about 2.5 mm and about 10 mm.

In an embodiment disclosed the projection is substantially frustoconical shaped.

In an embodiment disclosed the projection is substantially shaped as a cone tip, a wedge-shape, a wedge-tip, a random clustering or a combination thereof.

In an embodiment disclosed the projection is composed of one or more of substantially tungsten carbide, hardened metal, carbon steel or stainless steel.

In an embodiment disclosed the projection is coupled to the substantially frustoconical-shaped section of the outer surface of the drill bit.

In an embodiment disclosed the projection is integral with the outer surface of the drill bit.

In an embodiment disclosed the projection is pressed into the outer surface of the drill bit.

In an embodiment disclosed the leading face comprises a plurality of pegs extending longitudinally from the leading face, adapted to facilitate drilling.

In an embodiment disclosed the leading face is substantially a saw tooth face.

In an embodiment disclosed the leading face defines an elliptical plane having a pitch greater than 0 degrees.

In an embodiment disclosed the pitch is between about 15 degrees and about 30 degrees.

In an embodiment disclosed the pitch is about 24 degrees.

In an embodiment disclosed at least a portion of the leading face is angled at a face angle.

In an embodiment disclosed the face angle is greater than 0 degrees.

In an embodiment disclosed the face angle is between about 15 degrees and about 30 degrees.

In an embodiment disclosed the face angle is about 24 degrees.

In an embodiment disclosed the projection comprises a tungsten carbide coating providing a plurality of tungsten carbide clusters (clusterite) spaced about the frustoconical-shaped section.

In an embodiment disclosed the frustoconical-shaped section comprises a taper.

In an embodiment disclosed the taper is between about 2 degrees and about 8 degrees.

In an embodiment disclosed the taper is about 5 degrees.

In a further aspect, the present disclosure provides the use of the tool as disclosed herein with an oil and gas well service rig or an oil and gas drilling rig.

In an embodiment disclosed the tool is used with a tubular.

In an embodiment disclosed the tool is used to remove debris from a wellbore.

In an embodiment disclosed the debris includes or is hard scale.

In a further aspect, the present disclosure provides a method for servicing a well having a defined wellbore restricted by debris, including inserting a clean-out string into the wellbore of the well, the clean-out string having a downhole tool as disclosed herein coupled thereto, and rotating the clean-out string to engage the downhole tool with the debris restricting the wellbore to remove the debris from the wellbore.

In an embodiment disclosed the method further includes circulating or reverse circulating a fluid through the well to carry the debris removed from the wellbore out of the well.

In an embodiment disclosed, inserting the clean-out string into the wellbore includes positioning the downhole tool within the wellbore at a point restricted by the debris.

In an embodiment disclosed, engaging the downhole tool with the debris restricting the wellbore comprises rotating the downhole tool to engage a projection of the downhole tool with the debris to grind down or break apart the debris within the wellbore.

In an embodiment disclosed the fluid is a drilling fluid or a well servicing fluid. In an embodiment, the drilling fluid or the well servicing fluid may be water.

In an embodiment disclosed the well is a hydrocarbon recovery well or a water well.

In an embodiment disclosed the debris comprises hard scale or well-bottom debris or both.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the present disclosure will now be described, by way of example only, with reference to the attached Figures.

FIG. 1 depicts a plurality of views of a downhole tool in accordance with an embodiment of the present disclosure, showing a plurality of frustoconical-shaped projections on the outer surface of the drill bit.

FIG. 2 depicts a top plan view of the downhole tool of FIG. 1, showing the bit bore defined by the drill bit and a plurality of frustoconical-shaped projections on the outer surface of the drill bit.

FIG. 3 depicts a side-elevation view of the downhole tool of FIG. 2, showing the bit bore defined by the drill bit (in dashed lines), a plurality of frustoconical-shaped projections on the outer surface of the drill bit, with the first end (typically well bottom) of the drill bit defining a leading face and the second end (typically well top) of the drill bit adapted to engage a drive pipe.

FIG. 4 depicts of a perspective view of the downhole tool of FIG. 2, showing the first end of the drill bit defining a leading face comprising a plurality of teeth-like projections adapted to facilitate drilling, in accordance with an embodiment of the present disclosure.

FIG. 5 depicts a side-elevation view of a downhole tool in accordance with an embodiment of the present disclosure, showing a plurality of wedge-tip projections on the outer surface of the drill bit, with the first end of the drill bit defining a leading face and the second end of the drill bit adapted to engage a drive pipe.

FIG. 6 depicts a plurality of views of a downhole tool in accordance with an embodiment of the present disclosure, showing a plurality of wedge-tip projections on the outer surface of the drill bit, with a first end of the drill bit defining a leading face and a second end of the drill bit adapted to engage a drive pipe, the leading face having a substantially saw-tooth face.

FIG. 7 depicts a side-elevation view of the downhole tool of FIG. 6, showing a plurality of wedge-tip projections on the outer surface of the drill bit, with the first end of the drill bit defining a leading face having a substantially saw-tooth face and the second end of the drill bit adapted to engage a drive pipe.

FIG. 8 depicts a perspective view of a downhole tool in “Normal Circulation” in accordance with an embodiment of the present disclosure in use in a wellbore.

FIG. 9 depicts a perspective view of a downhole tool in “Reverse Circulation” in accordance with an embodiment of the present disclosure in use in a wellbore.

DETAILED DESCRIPTION

A downhole tool as described herein may be used to break up or grind down and remove scale and debris that has built up within a defined wellbore, including but not limited to cased wellbores, uncased wellbores, and combinations thereof including but not limited to wellbores with barefoot completions, the wellbore being a wellbore of, for example, a hydrocarbon recovery well (e.g. producing one or more of oil, gas and water), a water well, an injection well, or other well. Generally, the downhole tool comprises a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe; and a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from a wellbore. The scale and debris are at least partially removed from the wellbore when broken up or ground down by the downhole tool comprising the projection and carried to the surface through the circulation of drilling fluid. In some examples, the projection comprises a plurality of projections. In some examples, the downhole tool is used on a well servicing tubing string that, generally, is top-driven. In other examples, the downhole tool is used with a mud motor, or down-hole motor. In a preferred embodiment, the present disclosure is preferably used with drive that allows the use of reverse circulation whereby returning fluids and cleaned out debris are conveyed to the surface through the internal bore of the bit and clean out string.

FIGS. 1 to 4 show a downhole tool having a drill bit 100, the drill bit having an outer surface for engaging a wellbore and defining a bit bore 2. The drill bit 100 has a first end 4 defining a leading face and a second end 5 adapted to engage a drive pipe, with the outer surface having a substantially cylinder-shaped section 7 abutting the second end 5, and a substantially frustoconical-shaped section 6 abutting the substantially cylinder-shaped section 7 and terminating at the first end 4. The first end 4 defines a leading face that comprises a plurality of pegs 9 adapted to facilitate drilling, the pegs 9 extending longitudinally from the leading face. In some examples, the pegs 9 are absent. In some examples, the substantially cylinder-shaped section 7 is proximal the second end 5. In other examples, the substantially frustoconical-shaped section 6 is proximal the substantially cylinder-shaped section 7 and the first end 4. In some examples, the substantially cylinder-shaped section 7 of the outer surface acts to centralizing the drill bit 100 in the wellbore. In other examples, the substantially cylinder-shaped section 7 of the outer surface is sized to provide an annular gap within the wellbore. In some examples, the annular gap is from about 10 mm to about 50 mm in size.

The drill bit 100 has a projection 3 coupled to the substantially frustoconical-shaped section 6 of the outer surface, the projection 3 being adapted to remove (e.g., break up or grind down) debris from a wellbore. The projection 3 extends substantially perpendicular from the outer surface 6, and is substantially frustoconical-shaped. In some examples the projection 3 is a wedge tipped shape, and in others it is cone-shaped. In other cases the projection 3 is made up of randomly clustered cutting surfaces. The drill bit 100 may utilize one or more type/shape of projection 3. In some examples, the projection 3 is composed of tungsten carbide. In some examples, the projection 3 is integral with the outer surface of the drill bit 100. In other examples, the projection 3 is pressed into the outer surface of the drill bit 100. The projection 3 comprises a plurality of projections, each of the projections being circumferentially and longitudinally displaced relative to each other to spiral along the substantially frustoconical-shaped section 6 of outer surface of the drill bit 100. In some examples, each of the plurality of projections is circumferentially displaced relative to each other. In other examples, each of the plurality of projections is longitudinally displaced relative to each other. In other examples the projections are clustered randomly.

FIG. 5 shows a downhole tool having a drill bit 102, the drill bit 102 having an outer surface for engaging a wellbore and defining a bit bore (not shown). The drill bit 102 has a first end 4A defining a leading face and a second end 5A adapted to engage a drive pipe, with the outer surface having a substantially cylinder-shaped section 7A abutting the second end 5A, and a substantially frustoconical-shaped section 6A abutting the substantially cylinder-shaped section 7A and terminating at the first end 4A. In some examples, the substantially cylinder-shaped section 7A is proximal the second end 5A. In other examples, the substantially frustoconical-shaped section 6A is proximal the substantially cylinder-shaped section 7A and the first end 4A. In some examples, the substantially cylinder-shaped section 7A of the outer surface acts to centralizing the drill bit 102 in the wellbore. In other examples, the substantially cylinder-shaped section 7A of the outer surface is sized to provide an annular gap within the wellbore. In some examples, the annular gap is from about 10 mm to about 50 mm in size.

The drill bit 102 has a projection 10 that is substantially shaped as a wedge-tip. The projection 10 extends substantially perpendicular from the substantially frustoconical-shaped section 6A of the outer surface of the drill bit 102. In some examples, the projection 10 is composed of tungsten carbide. In some examples, the projection 10 is integral with the outer surface of the drill bit 102. In other examples, the projection 10 is pressed into the outer surface of the drill bit 102. The projection 10 comprises a plurality of projections, each of the projections being circumferentially and longitudinally displaced relative to each other to spiral along the substantially frustoconical-shaped section 6A of the outer surface of the drill bit 102. In some examples, each of the plurality of projections is circumferentially displaced relative to each other. In other examples, each of the plurality of projections is longitudinally displaced relative to each other.

FIGS. 6 and 7 show a downhole tool having a drill bit 104, the drill bit having an outer surface for engaging a wellbore and defining a bit bore 2B. The drill bit 104 has a first end 4B defining a leading face and a second end 5B adapted to engage a drive pipe, with the outer surface having a substantially cylinder-shaped section 7B abutting the second end 5B, and a substantially frustoconical-shaped section 6B abutting the substantially cylinder-shaped section 7B and terminating at the first end 4B. The first end 4B defines a leading face that has a substantially saw-tooth face 8 adapted to facilitate drilling. In some examples, the saw-tooth face 8 is absent. The drill bit 104 also has hardfacing strips 11 to provide additional strength to the drill bit 104. In some examples, the hardfacing strips 11 are absent.

In some examples, the substantially cylinder-shaped section 7B is proximal the second end 5B. In other examples, the substantially frustoconical-shaped section 6B is proximal the substantially cylinder-shaped section 7B and the first end 4B. In some examples, the substantially cylinder-shaped section 7B of the outer surface acts to centralizing the drill bit 104 in the wellbore. In other examples, the substantially cylinder-shaped section 7B of the outer surface is sized to provide an annular gap within the wellbore. In some examples, the annular gap is from about 10 mm to about 50 mm in size.

The drill bit 104 has a projection 10B that is substantially shaped as a wedge-tip. The projection 10B extends substantially perpendicular from the substantially frustoconical-shaped section 6B of the outer surface of the drill bit 104. In some examples, the projection 10B is composed of tungsten carbide. In some examples, the projection 10B is integral with the outer surface of the drill bit 104. In other examples, the projection 10B is pressed into the outer surface of the drill bit 104. The projection 10B comprises a plurality of projections, each of the projections being circumferentially and longitudinally displaced relative to each other to spiral along the substantially frustoconical-shaped section 6B of the outer surface of the drill bit 104. In some examples, each of the plurality of projections is circumferentially displaced relative to each other. In other examples, each of the plurality of projections is longitudinally displaced relative to each other.

Referring to FIG. 8, drill bit 100 is attached to drive 20 and inserted into a wellbore 30 until above or at debris 40. Rotation 45 (e.g. conventionally clockwise looking from above) of the drill bit 100 via drive 20, e.g. from a top drive or rotary drive at surface or a mud motor or downhole motor proximate the drill bit 100, causes the drill bit 100 to grind down or break up at least a portion and preferably substantially the debris 40. Circulation of fluid 50 sweeps or otherwise conveys the ground debris 60 to surface. While FIG. 8 illustrates normal circulation (being the fluid 50 conveyed down the pipe bore and up the annulus), as described herein, the invention may also utilize reverse circulation (being the fluid 50 conveyed down the annulus and up the pipe bore), see FIG. 9. While FIGS. 8 and 9 illustrate the wellbore 30 as being a substantially vertical portion, the invention may also be applied to wells having slanted, horizontal, lateral, angled, dogleg, and/or radiused sections. While FIGS. 8 and 9 illustrate the wellbore 30 as having a casing 70, as described herein, the invention may also be applied to uncased wellbores.

In an example, in use, the downhole tool having the drill bit 100, 102, 104 is attached in a conventional manner to, for example, a well service drilling rig drive pipe and run into an affected, already defined wellbore (e.g., a wellbore of an oil well, gas well, water well, or other well, etc.) that has a build-up of hard scale or debris. In some examples, the downhole tool is used on a well servicing tubing string that is top-driven. In other examples, the downhole tool is used with a mud motor, or down-hole motor. Once in the wellbore, the drill bit 100, 102, 104 is rotated in a conventional manner. The shape of the drill bit 100, 102, 104 and projection 3, 10, 10B coupled thereto allow the downhole tool to be used to grind down or break up and remove scale and debris from the wellbore as the drill bit 100, 102, 104 is rotated. As the downhole tool is run down the wellbore and the drill bit 100, 102, 104 rotated, fluids (e.g., drilling fluids, well-servicing fluids) are, for example, circulated down the drive pipe and delivered with a high hydraulic velocity at the leading face defined by the first end 4, 4A, 4B of the drill bit 100, 102, 104 due to the single bit bore 2, 2B of the drill bit 100, 102, 104. The fluids then carry the scale and debris removed from the wellbore by the downhole tool out of the wellbore via an annulus formed between the drive pipe and the wellbore. As needed, shark-tooth machining of the leading face defined by the first end 4, 4A, 4B of the drill bit 100, 102, 104 provides for a more aggressive bite when required (e.g., teeth-like projections 9 of drill bit 100 in FIGS. 1 to 4, and substantially saw-tooth face 8 of drill bit 104 in FIGS. 6 and 7).

Referring to FIG. 9, the fluids are reverse circulated down the annulus and then carry the scale and debris out of the wellbore via the internal bore of the drive pipe. In an example, in use, the downhole tool having the drill bit 100, 102, 104 is attached in a conventional manner to, for example, a well service drilling rig drive pipe and run into an affected, already defined wellbore (e.g., a wellbore of an oil well, gas well, water well, etc.) that has a build-up of hard scale or debris. In a preferred example, the present disclosure is used with a drive that allows the use of reverse circulation whereby returning fluids and cleaned out debris are conveyed to the surface through the internal bore of the bit and clean out string. In some examples, the downhole tool is used on a well servicing tubing string that is top-driven. Once in the wellbore, the drill bit 100, 102, 104 is rotated in a conventional manner. The shape of the drill bit 100, 102, 104 and projection 3, 10, 10B coupled thereto allow the downhole tool to be used to grind down or break up and remove scale and debris from the wellbore as the drill bit 100, 102, 104 is rotated. As the downhole tool is run down the wellbore and the drill bit 100, 102, 104 rotated, fluids (e.g., drilling fluids, well-servicing fluids) are, for example, reverse circulated down the annulus formed between the drive pipe and the wellbore and delivered with a high hydraulic velocity at the leading face defined by the first end 4, 4A, 4B of the drill bit 100, 102, 104 due to the single bit bore 2, 2B of the drill bit 100, 102, 104. The fluids then carry the scale and debris removed from the wellbore by the downhole tool out of the wellbore to surface via the drive pipe bore.

A combination or sequence of circulation, reverse circulation, no circulation may be used. Similarly, a combination or sequence of rotating or non-rotating may be used.

In another example, in use, the downhole tool having the drill bit 100, 102, 104 is attached to the bottom of a clean-out string, and run into an affected well with an already defined wellbore to break up or grind out built-up scale and other well-bottom debris. Such debris may then be reverse circulated out of the well during a clean out operation. As used herein, a clean-out string is a string of tubing assembled specifically to clean out a well. The well may be, for example, an oil well, gas well, or water well that has its performance restricted by well-bottom debris.

The clean-out string is generally set up by a service rig attending the wellsite. For example, if in use, a production tubing string is first removed from the affected well and set aside in a suitable manner. The downhole tool having the drill bit 100, 102, 104 is attached to the bottom of the clean-out string using a make-up torque suitable for the threads of the clean-out string. In an example, the downhole tool having the drill bit 100, 102, 104 may optionally be used with one or more specialized joints in the clean-out string.

The clean-out string is then inserted into, for example, the casing of the affected well and lowered to the point of debris obstruction. Standard industry well servicing practices may be followed during the insertion of the clean-out string. Once the downhole tool having the drill bit 100, 102, 104 is located at the point of debris obstruction, the clean-out string is rotated, and the well is reverse circulated, with well servicing fluid being pumped down to the well-bottom through the annulus between the string and the casing. The well servicing fluid is returned to the surface through the single bit bore 2, 2B of the drill bit 100, 102, 104 and clean-out string.

As would be understood by a person skilled in the art, the well servicing fluid pump rates need to be sufficient to create a fluid velocity that will carry debris up through the center bore of the clean-out string. At the same time that the well is being reverse circulated, the clean-out string is rotated to create a grinding action with the downhole tool having the drill bit 100, 102, 104, where common industry practice would determine the rotation rate.

As the clean-out string is rotated, the projection 3, 10, 10B coupled to the drill bit 100, 102, 104 grinds off or breaks up the debris until it is small enough to be lifted by the well servicing fluid. The flow of the well servicing fluid then carries the debris to the surface where it is removed from the well servicing fluid in a conventional manner.

Upon completion of the clean out, the clean-out string is pulled out of the well bore, and the downhole tool having the drill bit 100, 102, 104 is inspected and set aside for use in another well service job. The normal service string is then reinserted into the wellbore and well put back into normal service.

In examples, the downhole tool having the drill bit 100, 102, 104 may be used with an well service drilling rig, such as an oil well service drilling rig. In other examples, the downhole tool having the drill bit 100, 102, 104 may be used with a well service drilling rig drill pipe. In yet other examples, the downhole tool having the drill bit 100, 102, 104 may be used with a drill pipe. In other examples, the downhole tool having the drill bit 100, 102, 104 may be used to remove debris from a wellbore, wherein the debris may comprise hard scale.

Generally, the downhole tool may be used with tubulars, including but not limited to pipe, drill pipe, tubing, coiled tubing, jointed tubing. Generally, the downhole tool may be rotated from surface, for example by a top drive or rotary table or may be rotated proximate the downhole tool, for example by a mud motor or downhole-motor. In a preferred embodiment, the present disclosure is preferably used with drive that allows the use of reverse circulation whereby returning fluids and cleaned out debris are conveyed to the surface through the internal bore of the bit and clean out string. The supply of well servicing fluid, and circulation or reverse circulation, as the case may be, as well as the removal of debris from the well servicing fluid, is provided from/at surface.

Apart from hard scale, well bottom debris is loose debris that may originate from one or more sources within or associated with the wellbore. It may be hard debris that originates from within the completed formation or from formation fluids. Occasionally, hard scale or well bottom debris could result from mechanical debris from wellbore components. Hard scale or well bottom debris could also result from scale, consolidated or unconsolidated sand, iron sulfides, wax or a combination of one or more of the above. When the material is hard, the disclosed tool and methods break it up.

Embodiment 1. A downhole tool, comprising: a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe; and a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from the wellbore.

Embodiment 2. The tool of embodiment 1, wherein the projection comprises a plurality of projections.

Embodiment 3. The tool of embodiment 2, wherein each of the plurality of projections is circumferentially displaced relative to each other.

Embodiment 4. The tool of embodiment 2 or 3, wherein each of the plurality of projections is longitudinally displaced relative to each other.

Embodiment 5. The tool of any one of embodiments 2 to 4, wherein each of the plurality of projections are circumferentially and longitudinally displaced relative to each other and spiral along the outer surface of the drill bit.

Embodiment 6. The tool of any one of embodiments 1 to 5, wherein the outer surface of the drill bit has a substantially frustoconical-shaped section proximal the first end, and a substantially cylinder-shaped section.

Embodiment 7. The tool of any one of embodiments 1 to 6, wherein the outer surface of the drill bit has a substantially cylinder-shaped section abutting the second end, and a substantially frustoconical-shaped section abutting the substantially cylinder-shaped section and terminating at the first end.

Embodiment 8. The tool of any one of embodiments 1 to 7, wherein the projection extends substantially perpendicular from the outer surface of the drill bit.

Embodiment 9. The tool of embodiment 8, wherein the projection extends from the outer surface between about 1 mm and about 10 mm.

Embodiment 10. The tool of any one of embodiments 7 to 9 when dependent on embodiment 2, wherein at least one of the plurality of projections extends beyond an outer diameter of the cylinder-shaped section, by an undercut height.

Embodiment 11. The tool of embodiment 10, wherein the undercut height is a maximum of 10 mm.

Embodiment 12. The tool of embodiment 11, wherein the undercut height is between about 2.5 mm and about 10 mm.

Embodiment 13. The tool of any one of embodiments 1 to 12, wherein the projection is substantially frustoconical-shaped.

Embodiment 14. The tool of any one of embodiments 1 to 12, wherein the projection is substantially shaped as a cone tip, a wedge-shape, a wedge-tip, a random clustering or a combination thereof.

Embodiment 15. The tool of any one of embodiments 1 to 14, wherein the projection is composed of one or more of substantially tungsten carbide, hardened metal, carbon steel or stainless steel.

Embodiment 16. The tool of embodiment 6 or 7, or any one of embodiments 8 to 15 when dependent on embodiment 6 or 7, wherein the projection is coupled to the substantially frustoconical-shaped section of the outer surface of the drill bit.

Embodiment 17. The tool of any one of embodiments 1 to 16, wherein the projection is integral with the outer surface of the drill bit.

Embodiment 18. The tool of any one of embodiments 1 to 16, wherein the projection is pressed into the outer surface of the drill bit.

Embodiment 19. The tool of any one of embodiments 1 to 18, wherein the leading face comprises a plurality of pegs extending longitudinally from the leading face, adapted to facilitate drilling.

Embodiment 20. The tool of any one of embodiments 1 to 18, wherein the leading face is substantially a saw-tooth face.

Embodiment 21. The tool of any one of embodiments 1 to 20, wherein the leading face defines an elliptical plane having a pitch greater than 0 degrees.

Embodiment 22. The tool of embodiment 21, wherein the pitch is between about 15 degrees and about 30 degrees.

Embodiment 23. The tool of embodiment 22, wherein the pitch is about 24 degrees.

Embodiment 24. The tool of any one of embodiment 1 to 20, wherein at least a portion of the leading face is angled at a face angle.

Embodiment 25. The tool of embodiment 24, wherein the face angle is greater than 0 degrees.

Embodiment 26. The tool of embodiment 25, wherein the face angle is between about 15 degrees and about 30 degrees.

Embodiment 27. The tool of embodiment 26, wherein the face angle is about 24 degrees.

Embodiment 28. The tool of any one of embodiments 6 or 7 to 27 when dependent on embodiment 6, wherein the projection comprises a tungsten carbide coating providing a plurality of tungsten carbide clusters (clusterite) spaced about the frustoconical-shaped section.

Embodiment 29. The tool of any one of embodiments 6 or 7 to 28 when dependent on embodiment 6, wherein the frustoconical-shaped section comprises a taper.

Embodiment 30. The tool of embodiment 29, wherein the taper is between about 2 degrees and about 8 degrees.

Embodiment 31. The tool of embodiment 30, wherein the taper is about 5 degrees.

Embodiment 32. Use of the tool of any one of embodiments 1 to 31 with an oil and gas well service rig or an oil and gas drilling rig.

Embodiment 33. Use of the tool of any one of embodiments 1 to 31 with a tubular.

Embodiment 34. Use of the tool of any one of embodiments 1 to 31 to remove debris from a wellbore.

Embodiment 35. The use of embodiment 34, wherein the debris comprises hard scale.

Embodiment 36. A method for servicing a well having a defined wellbore restricted by debris, comprising: inserting a clean-out string into the wellbore of the well, the clean-out string having a downhole tool of any one of embodiments 1 to 31 coupled thereto; and rotating the clean-out string to engage the downhole tool with the debris restricting the wellbore to remove the debris from the wellbore.

Embodiment 37. The method of embodiment 36, further comprising circulating or reverse circulating a fluid through the well to carry the debris removed from the wellbore out of the well.

Embodiment 38. The method of embodiment 36 or 37, wherein inserting the clean-out string into the wellbore comprises positioning the downhole tool within the wellbore at a point restricted by the debris.

Embodiment 39. The method of any one of embodiments 36 to 38, wherein engaging the downhole tool with the debris restricting the wellbore comprises rotating the downhole tool to engage a projection of the downhole tool with the debris to grind down or break apart the debris within the wellbore.

Embodiment 40. The method of any one of embodiment 36 to 39, wherein the fluid is a drilling fluid or a well-servicing fluid.

Embodiment 41. The method of any one of embodiments 36 to 40, wherein the well is a hydrocarbon recovery well or a water well.

Embodiment 42. The method of any one of embodiments 36 to 41, wherein the debris comprises hard scale or well-bottom debris or both.

The embodiments described herein are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art. The scope of the claims should not be limited by the particular embodiments set forth herein, but should be construed in a manner consistent with the specification as a whole.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modification as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

What is claimed is:
 1. A downhole tool, comprising: a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe; and a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from the wellbore.
 2. The tool of claim 1, wherein the projection comprises a plurality of projections.
 3. The tool of claim 2, wherein each of the plurality of projections is circumferentially displaced relative to each other.
 4. The tool of claim 3, wherein each of the plurality of projections is longitudinally displaced relative to each other.
 5. The tool of claim 4, wherein each of the plurality of projections are circumferentially and longitudinally displaced relative to each other and spiral along the outer surface of the drill bit.
 6. The tool of claim 5, wherein the outer surface of the drill bit has a substantially frustoconical-shaped section proximal the first end, and a substantially cylinder-shaped section.
 7. The tool of claim 6, wherein the outer surface of the drill bit has a substantially cylinder-shaped section abutting the second end, and a substantially frustoconical-shaped section abutting the substantially cylinder-shaped section and terminating at the first end.
 8. The tool of claim 7, wherein the projection extends substantially perpendicular from the outer surface of the drill bit.
 9. The tool of claim 8, wherein the projection extends from the outer surface between about 1 mm and about 10 mm.
 10. The tool of claim 9, wherein at least one of the plurality of projections extends beyond an outer diameter of the cylinder-shaped section, by an undercut height.
 11. The tool of claim 10, wherein the undercut height is a maximum of 10 mm.
 12. The tool of claim 11, wherein the undercut height is between about 2.5 mm and about 10 mm.
 13. The tool of claim 1, wherein the projection is substantially frustoconical-shaped.
 14. The tool of claim 1, wherein the projection is substantially shaped as a cone tip, a wedge-shape, a wedge-tip, a random clustering or a combination thereof.
 15. The tool of claim 1, wherein the projection is composed of one or more of substantially tungsten carbide, hardened metal, carbon steel or stainless steel.
 16. The tool of claim 6, wherein the projection is coupled to the substantially frustoconical-shaped section of the outer surface of the drill bit.
 17. The tool of claim 7, wherein the projection is coupled to the substantially frustoconical-shaped section of the outer surface of the drill bit.
 18. The tool of claim 1, wherein the projection is integral with the outer surface of the drill bit.
 19. The tool of claim 1, wherein the projection is pressed into the outer surface of the drill bit.
 20. The tool of claim 1, wherein the leading face comprises a plurality of pegs extending longitudinally from the leading face, adapted to facilitate drilling.
 21. The tool of claim 1, wherein the leading face is substantially a saw-tooth face.
 22. The tool of claim 20, wherein the leading face defines an elliptical plane having a pitch greater than 0 degrees.
 23. The tool of claim 21, wherein the leading face defines an elliptical plane having a pitch greater than 0 degrees.
 24. The tool of claim 22, wherein the pitch is between about 15 degrees and about 30 degrees.
 25. The tool of claim 24, wherein the pitch is about 24 degrees.
 26. The tool of claim 20, wherein at least a portion of the leading face is angled at a face angle.
 27. The tool of claim 21, wherein at least a portion of the leading face is angled at a face angle.
 28. The tool of claim 26, wherein the face angle is greater than 0 degrees.
 29. The tool of claim 28, wherein the face angle is between about 15 degrees and about 30 degrees.
 30. The tool of claim 29, wherein the face angle is about 24 degrees.
 31. The tool of claim 6, wherein the projection comprises a tungsten carbide coating providing a plurality of tungsten carbide clusters (clusterite) spaced about the frustoconical-shaped section.
 32. The tool of claim 6, wherein the frustoconical-shaped section comprises a taper.
 33. The tool of claim 32, wherein the taper is between about 2 degrees and about 8 degrees.
 34. The tool of claim 33, wherein the taper is about 5 degrees.
 35. In a downhole tool, comprising: a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe; and a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from the wellbore, the use of the tool with an oil and gas well service rig or an oil and gas drilling rig.
 36. In a downhole tool, comprising: a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe; and a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from the wellbore, the use of the tool with a tubular.
 37. In a downhole tool, comprising: a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe; and a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from the wellbore, the use of the tool to remove debris from a wellbore.
 38. The use of claim 37, wherein the debris comprises hard scale.
 39. A method for servicing a well having a defined wellbore restricted by debris, comprising: inserting a clean-out string into the wellbore of the well, the clean-out string having a downhole tool coupled thereto the downhole tool, comprising: a drill bit, the drill bit having an outer surface for engaging a wellbore and defining a bit bore, the drill bit having a first end defining a leading face and a second end adapted to engage a drive pipe; a projection coupled to the outer surface of the drill bit, the projection being adapted to remove debris from the wellbore, the use of the tool; and rotating the clean-out string to engage the downhole tool with the debris restricting the wellbore to remove the debris from the wellbore.
 40. The method of claim 39, further comprising circulating or reverse circulating a fluid through the well to carry the debris removed from the wellbore out of the well.
 41. The method of claim 39, wherein inserting the clean-out string into the wellbore comprises positioning the downhole tool within the wellbore at a point restricted by the debris.
 42. The method of claim 39, wherein engaging the downhole tool with the debris restricting the wellbore comprises rotating the downhole tool to engage a projection of the downhole tool with the debris to grind down or break apart the debris within the wellbore.
 43. The method of claim 40, wherein the fluid is a drilling fluid or a well-servicing fluid.
 44. The method of claim 39, wherein the well is a hydrocarbon recovery well or a water well.
 45. The method of claim 39, wherein the debris comprises hard scale or well-bottom debris or both. 